1. Technical Field
The present invention relates to a jitter injection circuit, an electronic device, and a test apparatus. In particular, the present invention relates to a jitter injection circuit that injects jitter having a predetermined amplitude to a transmission signal outputted from a transmission circuit and inputs the resulting transmission signal to a reception circuit, an electronic device that includes the jitter injection circuit therein, and a test apparatus that employs the jitter injection circuit.
2. Related Art
A test for measuring the jitter resistance of a device under test is known, as a test for a device under test such as a semiconductor circuit. The test tests the jitter resistance of a device under test, by changing the amplitude of jitter injected to an input signal to the device under test, and measuring the range of the jitter amplitude within which the device under test is able to be normally operated.
Furthermore, a technology to apply the above-mentioned test to a loopback test of a SerDes circuit is also known (e.g. Patent Document 1). In the test, jitter means is used to inject jitter having a desired amplitude to a signal outputted from a transmitter Tx of a SerDes circuit, and the resulting signal is inputted to a receiver Rx of the SerDes circuit. It is possible to measure the jitter resistance of the receiver Rx from the range of the amount of injected jitter within which the receiver Rx is normally operated.
[Patent Document 1] U.S. Pat. No. 7,017,087
For measuring the jitter resistance with accuracy, it is desirable to control the jitter amount included in a signal inputted to the receiver Rx with accuracy. However, the signal inputted to the receiver Rx includes jitter having been generated in the transmitter Tx and the like, in addition to jitter injected by the jitter injection means.
In view of this, in conventional tests, a measurement value of jitter resistance will have an error due to the jitter caused in the transmitter Tx and the like. Although it could be possible to control jitter caused in the transmitter Tx and the like, it is difficult to control the jitter caused in the transmitter Tx and the like, with accuracy.